Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
  • B41C1/00—Forme preparation
  • B41C1/02—Engraving; Heads therefor
  • B41C1/04—Engraving; Heads therefor using heads controlled by an electric information signal
  • B41C1/05—Heat-generating engraving heads, e.g. laser beam, electron beam
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
  • Y10S430/146—Laser beam

Definitions

• the invention relates to a method for producing thermally crosslinked, laser-engravable flexographic printing elements, the production of relief printing plates from the laser-engravable flexographic printing elements, and the thermally uncrosslinked flexographic printing elements.
• EP-A 0 640 043 discloses the production of a soot-containing, elastomeric layer by means of photo crosslinking.
• this layer is only 0.076 mm thick, while the typical thickness of commercially available flexographic printing plates is 0.5 to 7 mm.
• thermocrosslinkable, flexible printing plates based on thermoplastic elastomers are produced in an elegant manner produced by extrusion and calendering at elevated temperatures using thermally stable photoinitiators.
• thermally decomposing initiators are used, since premature crosslinking can occur due to the high working temperatures and the high shear in the production of the thermally crosslinkable mixture in the extruder.
• low working temperatures of well below 100 ° C are required, so that processing in a twin-screw extruder, for example, is ruled out.
• the object of the invention is to provide a method for producing laser-engravable flexographic printing plates with a thermally cross-linked, elastomeric relief-forming layer.
• the object is achieved by a method for producing a laser-engravable flexographic printing element, comprising a thermally cross-linked, elastomeric relief-forming layer E, with the steps: (i) Production of a melir layer composite, at least comprising a two-layer composite comprising a depot layer D and an uncrosslinked precursor layer V directly adjacent to the depot layer D, for the relief-forming layer E, and optionally further layers and carrier and / or protective films, the precursor layer V
• a multilayer composite at least comprising a two-layer composite, is produced from the depot layer D and the uncrosslinked precursor layer V directly adjacent to the depot layer D for the relief-forming layer E.
• the precursor layer V contains at least one elastomeric binder as a component
• binders which are also used for the production of photopolymerizable flexographic printing plates can be used as elastomeric binders. In principle, both elastomeric binders and thermoplastic elastomeric binders are suitable. Examples of suitable binders are the known three-block copolymers of the SIS or SBS type, which can also be completely or partially hydrogenated. Elastomeric polymers of the ethylene / propylene / diene type, ethylene / acrylic acid rubbers or elastomeric polymers based on acrylates or acrylate copolymers can also be used. Further examples of suitable polymers are disclosed in DE-A 22 15 090, EP-A 084 851, EP-A 819 984 or EP-A 553 662. Mixtures of two or more different binders can also be used.
• the type and the amount of the binder used are chosen by the person skilled in the art depending on the desired properties of the printing relief. As a rule, this is
• the precursor layer contains at least one ethylenically unsaturated monomer as component (b).
• ethylenically unsaturated monomers it is possible in principle to use those which are usually also used for the production of photopolymerizable flexographic printing elements.
• the monomers should be compatible with the binders and should have at least one polymerizable, ethylenically unsaturated double bond.
• Suitable monomers generally have a boiling point of more than 100 ° C. at atmospheric pressure and a molecular weight of up to 3,000 g / mol, preferably up to 2,000 g / mol.
• Esters or amides of acrylic acid or methacrylic acid with mono- or polyfunctional alcohols, amines, amino alcohols or hydroxy ethers and esters, styrene or substituted styrenes, esters of fumaric or maleic acid or AUyl compounds have proven to be particularly advantageous.
• Suitable monomers are butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, 1,4-butanediol diacrylate, 1,6-lexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol diacrylate, trimethylolpropane triacrylate, dioctyl fecylate and N-didyl fumarate.
• Mixtures of different monomers can also be used.
• the total amount of monomers is 5 to 30% by weight, preferably 5 to 20% by weight, based on the sum of components (a) to (d).
• the precursor layer can also contain an absorber for laser radiation as component (c).
• the precursor layer preferably contains such an absorber.
• Suitable absorbers for laser radiation have a high absorption in the range of the laser wavelength.
• absorbers are suitable which have a high absorption in the near infrared and in the longer-wave VIS range of the electromagnetic spectrum.
• Such absorbers are particularly suitable for absorbing the radiation from high-performance Nd-Y AG lasers (1064 ⁇ m) and from IR diode lasers, which typically have wavelengths between 700 and 900 nm and between 1200 and 1600 nm.
• Suitable absorbers for laser radiation in the infrared spectral range are highly absorbing dyes such as phthalocyanines, naphthalocyanines, cyanines, quinones, metal complex dyes such as dithiolenes or photochromic dyes.
• Suitable absorbers are inorganic pigments, in particular intensely colored inorganic pigments such as chromium oxides, iron oxides, carbon black or metallic particles.
• Finely divided soot types with a particle size between 10 and 50 nm are particularly suitable as absorbers for laser radiation.
• suitable absorbers for laser radiation are iron-containing solids, in particular intensely colored iron oxides.
• iron oxides are commercially available and are usually used as color pigments or as pigments for magnetic recording.
• Suitable absorbers for laser radiation are, for example, FeO, goethite (alpha-FeOOH), Akaganeit (beta-FeOOH), lepidocrocite (gamma-FeOOH), hematite (alpha-Fe 2 O 3 ), maghemite (gamma-Fe 2 O 3) , magnetite (Fe 3 O) or Berthollide.
• doped iron oxides or mixed oxides of iron with other metals can be used.
• Examples of mixed oxides are Umbra Fe O 3 xn MnO 2 or Fe x Al ( i_ x yQOH, in particular various spinel black pigments such as Cu (Cr, Fe) 2 O, Co (Cr, Fe) 2 O 4 or Cu (Cr, Fe , Mn) 2 ⁇ .
• Examples of dopants are, for example, P, Si, Al, Mg, Zn or Cr To control particle shape.
• the iron oxides can also be coated. Such coatings can be applied, for example, in order to improve the dispersibility of the particles.
• These coatings can consist, for example, of inorganic compounds such as SiO 2 and / or A1OOH.
• organic coatings for example organic adhesion promoters such as aminopropyl (trimethoxy) silane, can also be applied.
• Particularly suitable absorbers for laser radiation are FeOOH, Fe 2 O 3 and Fe 3 O 4, most preferably Fe O 4.
• the size of the iron-containing, inorganic solids used, in particular the iron oxides, is selected by the person skilled in the art depending on the desired properties of the recording material. Solids with an average particle size of more than 10 ⁇ m are usually unsuitable. Since iron oxides in particular are anisometric, this information relates to the longest axis.
• the particle size is preferably less than 1 ⁇ m. So-called transparent iron oxides can also be used, which have a particle size of less than 0.1 ⁇ m and a specific surface area of up to 150 m 2 / g.
• Iron-containing pigments are also suitable as absorbers for laser radiation. Particularly suitable are acicular or rice-shaped pigments with a length between 0.1 and 1 ⁇ m. Such pigments are known as magnetic pigments for magnetic recording. In addition to iron, other dopants such as Al, Si, Mg, P, Co, Ni, Nd or Y can also be present, or the iron metal pigments can be coated with it. Ferrous metal pigments are surface oxidized to protect them against corrosion and consist of a possibly doped iron core and a possibly doped iron oxide shell.
• At least 0.1% by weight of absorber based on the sum of all components (a) to (d), is used.
• the amount of absorber added is selected by the person skilled in the art depending on the properties of the laser-engravable flexographic printing element that are desired in each case. In this context, the person skilled in the art will take into account that the absorbers added not only influence the speed and efficiency of the engraving of the elastomeric layer by laser, but also other properties of the flexographic printing element, such as, for example, its hardness, elasticity, thermal conductivity or ink acceptance. As a rule, therefore, more than 20% by weight of absorbers are unsuitable for laser radiation with respect to the sum of all components of the laser-engravable elastomer layer. Is preferably the amount of the absorber for laser radiation is 0.5 to 15% by weight and particularly preferably 0.5 to 10% by weight.
• the precursor layer V can optionally contain further additives as component (d) for setting the desired properties of the relief layer.
• additives are plasticizers, fillers, dyes, compatibilizers or dispersing agents.
• the amount of such further constituents should generally not exceed 20% by weight, preferably 10% by weight, based on the sum of components (a) to (d).
• the depot layer D also contains an elastomeric binder as component (e).
• e elastomeric binder
• the same elastomeric binders can be used that are also used in the precursor layer; the same elastomeric binders are preferably used in the precursor and depot layers.
• the depot layer D contains at least one thermally decomposing polymerization initiator as component (f).
• Suitable polymerization initiators are in principle all thermal initiators which are used for free-radical polymerization, such as peroxides, hydroperoxides or azo compounds.
• Suitable thermal initiators disintegrate into radicals at a high reaction rate only in the final step of the process according to the invention, thermal crosslinking. They are largely thermally stable in the preceding process steps of melting, mixing, extruding and calendering or casting from solution or dispersion, evaporation of the solvent and lamination.
• the term “largely thermally stable” means that the initiators disintegrate so slowly at most in the course of carrying out these steps of the process according to the invention that the layer and / or the mixture can only be crosslinked to a minor extent by polymerization Stability of an initiator is usually indicated by the temperature of the lO h half-life lO h-t ⁇ / 2 , that is to say the temperature at which 50% of the original amount of initiator after 10 h Radicals have decayed. Further details can be found in "Encylopedia of Polymer Science and Engineering", vol. 11, pages lff., John Wiley & Sons, New York, 1988.
• Initiators which are particularly suitable for carrying out the process according to the invention usually have a 10 h-t ⁇ / 2 of at least 60 ° C, preferably of at least 70 ° C. Particularly suitable initiators have a 10 h-t ⁇ / 2 of 80 ° C to 150 ° C.
• Suitable initiators include certain peroxy esters, such as t-butyl peroctoate, t-amyl peroctoate, t-butyl peroxy isobutyrate, t-butyl peroxymaleic acid, t-amyl perbenzoate, di-t-butyl diperoxyphthalate, t-butyl perbenzoate, t-butyl peracetate or 2,5-di ( - peroxy) -2,5-dimethylhexane, certain diperoxyketals such as l, l-di (t-amylperoxy) cyclohexane, l, l-di (t-butylperoxy) cyclohexane, 2,2-di (t-butylperoxy) butane or ethyl 3,3-di (t-butylperoxy) butyrate, certain dialkyl peroxides such as di-t-butyl peroxide, t-buty
• azo compounds such as 1- (t-butylazo) formamide, 2- (t-butylazo) isobutyronitrile, 1 - (t-butylazo) cyclohexane carbonitrile, 2- (t-butylazo) -2-methylbutanitrile, 2.2 '-azobis (2-actoxypropane), l, l'-azobis (cyclohexane carbonitrile), 2,2'-azobis (isobutyronitrile) or 2,2'-azobis (2-methylbutanenitrile).
• the concentration of the thermally disintegrating initiators in the depot layer depends on the thickness of the depot layer relative to the thickness of the laser-engravable, relief-forming elastomeric layer.
• the concentration of the thermally disintegrating polymerization initiators after the diffusion in and before the thermal crosslinking in the precursor layer is usually about 1 to 5% by weight, preferably about 2 to 3% by weight, based on the sum of all of those in the precursor layer present components.
• the thickness of the depot layer is usually half to 1/30 of the total thickness of the precursor layer and the depot layer taken together, for example 1/10 of the total thickness of both layers.
• the concentration of the thermally decomposing polymerization initiators in the depot layer is twice to 30 times the desired concentration of the polymerization initiators after diffusion into the precursor layer, for example with a layer thickness of the depot layer of 1/10 of Total layer thickness of both layers 20 to 30 wt .-%, based on the sum of components (e) to (h).
• the total thickness of relief-forming elastomeric layer D or precursor layer V and depot layer D is generally 0.4 to 7 mm.
• the depot layer can optionally contain an absorber for laser light as component (g). Suitable absorbers are the absorbers mentioned above as component (c) in the amounts specified there.
• the depot layer contains an absorber if, according to one embodiment of the method according to the invention, it remains on the printing side of the flexographic printing element during laser engraving and is laser-engraved together with the relief-forming layer E.
• the depot layer can optionally contain further additives as component (h) for adjusting the properties of the depot layer, such as plasticizers, fillers, dyes, compatibilizers or dispersing agents, in amounts of up to 20% by weight, preferably up to 10% by weight.
• further additives such as plasticizers, fillers, dyes, compatibilizers or dispersing agents, in amounts of up to 20% by weight, preferably up to 10% by weight.
• the two-layer composite of depot layer D and precursor layer V can be produced in different ways.
• the two-layer composite is not isolated, but is produced in the context of a multi-layer composite which comprises the two-layer composite and, in addition, further layers, carrier and / or protective films which are customary in laser-engravable flexographic printing elements or in general in flexographic printing elements.
• the multilayer composite is usually delimited by a dimensionally stable carrier film on one side and by a removable protective film on the other side, or else by two protective films.
• a customary adhesive layer can be present between a depot layer D and a carrier film coated with this.
• the printing side of the elastomeric, laser-engravable relief-forming layer or, optionally, an overlying, laser-engravable depot layer D can have an upper layer to improve the printing properties.
• a peelable protective film can be coated with a release layer.
• Suitable dimensionally stable supports S are plates and foils made from metals such as steel, aluminum, copper or nickel or from plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyamide, polycarbonate, optionally also fabrics and nonwovens, such as glass fiber fabrics and Composite materials made of glass fibers and plastics.
• Plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyamide, polycarbonate, optionally also fabrics and nonwovens, such as glass fiber fabrics and Composite materials made of glass fibers and plastics.
• Dimensionally stable carrier films such as polyester films, in particular PET or PEN films, are particularly suitable as dimensionally stable carriers. The thickness of the carrier film is generally 75 to 225 ⁇ m.
• the carrier film can be coated with an adhesive layer A.
• the multilayer element can comprise a thin top layer T on the precursor layer V or the laser-engravable depot layer D.
• Such an upper layer allows parameters such as roughness, abrasiveness, surface tension, surface stickiness or solvent resistance on the surface to be changed for printing behavior and ink transfer without affecting the relief-typical properties of the printing form, such as hardness or elasticity. Surface properties and layer properties can therefore be changed independently of one another in order to achieve an optimal printing result.
• the composition of the top layer is limited only to the extent that the laser engraving of the laser-engravable layer underneath it must not be impaired and the top layer must be removable together with it.
• the top layer should be thin compared to the laser-engravable layer. As a rule, the thickness of the top layer does not exceed 100 ⁇ m, preferably the thickness is between 1 and 80 ⁇ m, particularly preferably between 3 and 10 ⁇ m.
• the top layer itself should be easy to laser engrave.
• the multilayer element can also comprise a non-laser-engravable lower layer U, which is located between the carrier and the laser-engravable layer.
• U non-laser-engravable lower layer
• the mechanical properties of the relief printing plates can be changed without influencing the properties typical of the relief of the printing form.
• the multilayer element can optionally be protected against mechanical damage by a protective film P, for example made of PET, which is located on the top layer in each case and which must be removed by laser before engraving.
• the thickness of the protective films is generally 75 to 225 ⁇ m.
• the protective film can be coated with a “release layer” R.
• the thickness of the entire multilayer element is generally 0.7 to 7 mm.
• the formation of the precursor layer from a mixture containing the components (a) to (d) can take place before, during or after the precursor layer V or the mixture has been brought into contact with the depot layer D.
• the two-layer composite of D and V is produced by extruding a melt containing components (a) to (d) and calendering this melt between a first film and a second film, at least one film having the depot layer D is coated. Only one or both foils can be coated with the depot layer D, it being possible for further layers to be present between the depot layer D and the foil. Preferably only one film is coated with a depot layer. The other film can also be coated with further layers. Several layers can also be co-extruded, for example the precursor layer V and an overlying top layer T.
• the thermally crosslinkable flexographic printing elements can also be produced by conventional twin-screw extrusion and calendering of the crosslinkable layer.
• This process offers the advantage that small thickness tolerances are maintained, the components are mixed during the extrusion process and layer thicknesses> 1 mm are available.
• the two-layer composite of D and V is produced by laminating a first film coated with the depot layer D onto a second film coated with the precursor layer V. Additional layers can be present between depot layer D and the first film or between the precursor layer V and the second film.
• the two-layer composite of D and V is applied to a film which is coated with the depot layer D, and optionally subsequently, by applying a moldable mixture, solution or dispersion, comprising components (a) to (d) Made drying.
• the two-layer composite can be applied by applying a moldable melt and then pressing or by casting the solution or dispersion and then Drying can be made. It is also possible to cast several layers on top of one another, for example the precursor layer V and an upper layer T thereon.
• the thermally disintegrating polymerization initiators are allowed to diffuse into the precursor layer V from the depot layer D, preferably until they are homogeneously distributed in the precursor layer V.
• the diffusion of the polymerization initiators can be carried out by simply storing the multilayer elements over a period of 1 to 100 days, preferably 3 to 14 days.
• the diffusion can also take place at an elevated temperature, for example 30 to 80 ° C., which considerably shortens the required storage time. For example, the storage time is reduced from 7 days to 3 to 8 hours by increasing the temperature to 80 ° C.
• the depot layer D is removed in a third step (iii).
• the depot layer D is removed from the precursor layer, for example by delamination, after the diffusion.
• the adhesion between precursor layer V and depot layer D should be less than 1 N / 4 cm, preferably less than 0.5 N / 4 cm.
• the fourth step (iv) is followed by the thermal crosslinking of the precursor layer V to form the elastomeric, laser-engravable relief-forming layer E.
• the thermal crosslinking is carried out by heating the multilayer element to temperatures of generally 80 to 220 ° C., preferably 120 to 200 ° C. over a period of 2 to 30 minutes.
• the laser-engravable flexographic printing elements produced according to the invention serve as the starting material for the production of relief printing plates.
• the process involves first removing the protective film, if present.
• a printing relief is engraved into the recording material by means of a laser.
• Image elements are advantageously engraved in which the flanks of the image elements initially drop vertically and only widen in the lower region of the image element. This results in a good base of the pixels with a slight increase in tone value. However, flanks of the image points with different designs can also be engraved.
• Laser engraving is particularly suitable for CO 2 lasers with a wavelength of 10640 nm, but also for Nd-YAG lasers (1064 nm) and IR diode lasers or solid-state lasers, which typically have wavelengths between 700 and 900 nm and between 1200 and 1600 nm , However, lasers with shorter wavelengths can also be used, provided the laser is of sufficient intensity. For example, a frequency-doubled (532 nm) or frequency-tripled (355 nm) Nd-YAG laser can also be used, or an eximer laser (eg 248 nm).
• the image information to be engraved is transferred directly from the lay-out computer system to the laser apparatus.
• the lasers can be operated either continuously or in pulsed mode.
• the relief layer is removed very completely by the laser, so that intensive post-cleaning is generally not necessary. If desired, the printing plate obtained can still be cleaned. Such a cleaning step removes layer components which have been detached but which may not yet be completely removed from the plate surface. As a rule, simple wetting with water is completely sufficient.
• the depot layer D itself can be laser-engraved and is present on the printing side of the flexographic printing element, the relief in the depot layer D, which contains a laser light-absorbing material, and the relief-forming elastomeric layer E is engraved.
• the invention also relates to multilayer composites, comprising the two-layer composite comprising depot layer D and uncrosslinked precursor layer V.
• the multilayer element according to the invention has, in the order (I) - (VII) (I), a carrier film S, (II) optionally an adhesive layer A,
• the multilayer composite according to the invention has the sequence (I) - (V)
• the multilayer composite according to the invention has the order (I) - (V)
• the multilayer composite according to the invention has the sequence (I) - (VI)
• the non-adhesive, removable depot layer D can be removed before the thermal crosslinking, without the surface quality being significantly influenced.
• the binders in D are chosen such that the adhesion of D in the uncrosslinked state to V is less than 1 N / 4 cm, preferably less than 0.5 N / 4 cm.
• the supported peroxide depot layers D1 and D2 were attached to a dimensionally stable film, so that the applied peroxide depot layer could form a layer composite with the elastomer melt or with the moldable elastomer mixture during calendering.
• the layer composite D1 / V or the pressure element-forming layer E separated from the peroxide depot layer was crosslinked in whole or in part to form the layer E under the conditions described.
• a layer composite is understood to be the direct contact between the pressure element-forming layer V and at least one peroxide depot layer D1 or D2, insofar as this contact has existed at least for the duration of the union process, but is otherwise independent of a fixed period of contact after the union process.
• Example 1 of EP-A 0 326 977 The constituents of the printing plate formulation described in Example 1 of EP-A 0 326 977 were kneaded in a Haake kneader at an initial temperature of 150 ° C. and a rotational speed of 160 min -1 for a period of 10 minutes.
• the melt temperature fluctuated to constant 180 ° C and the torque reached a plateau at about 7 ⁇ m.
• the toluene extraction fraction of the kneaded mixture is 100%. Comparative Example B2
• a peroxide depot adhesive layer Dl was prepared as follows: 80 g of a styrene-isoprene-styrene block copolymers (Kraton ® D-1161NU of Shell) were dissolved in 185 ml of toluene at 110 ° C. After the solution had cooled to 60 ° C., 20 g of dicumyl peroxide were added and stirring was continued until the solution was clear and homogeneous (approximately 1 hour). The solution thus prepared was applied to a PET protective film in different layer thicknesses using a laboratory doctor. The layers obtained were then dried at room temperature for one day and finally at 35 ° C. for 3 hours.
• a low-oxygen melt was produced from the components of a nyloflex ® FAH printing plate using the above-mentioned process.
• the two-layer composite DI / V was then produced by calendering in the depot layers described, a commercially available PET film being used as the second dimensionally stable support.
• the two-layer composite DI / N from example la was heated to 160 ° C. for a period of 20 minutes in a normal air atmosphere after storage for one week.
• the two-layer composite DI / N from Example Ia was initially tempered for 3 hours at 80 ° C. after storage for one week and then heated to 160 ° C. in a normal air atmosphere for a period of 20 minutes.
• Another peroxide depot adhesive layer Dl was prepared as follows: 80 g of a styrene-butadiene / StyiOl-styrene block copolymers (Styroflex BX ® 6105, BASF) were dissolved in 150 ml of toluene at 110 ° C. After the solution had cooled to 60 ° C., 20 g of dicumyl peroxide were added and stirring was continued until the solution was clear and homogeneous (approximately 1 hour). The solution thus prepared was applied to a PET protective film in different layer thicknesses using a laboratory doctor. The layers obtained were then dried at room temperature for one day and finally at 35 ° C. for 3 hours.
• Styroflex BX ® 6105 StyiOl-styrene block copolymers
• a low-oxygen melt was produced from the components of a nyloflex ® FAH printing plate using the above-mentioned process.
• the two-layer composite DI / V was then produced by calendering in the depot layers described, a commercially available PET film being used as the second dimensionally stable support.
• the two-layer composite DI / N from example 2a was heated to 160 ° C. for a period of 20 minutes in a normal air atmosphere after storage for one week.
• the two-layer composite DI / N from Example 2a was first tempered for 3 hours at 80 ° C. after storage for one week and then heated to 160 ° C. in a normal air atmosphere for a period of 20 minutes.
• a peroxide depot release layer D2 was prepared as follows: 80 g of a polyamide Schmelzlclebers (Macromelt 6208 ®, Henkel) were dissolved in a mixture of 90 ml toluene and 90 ml 1-propanol at 95 ° C. After the solution had cooled to 60 ° C., 20 g of dicumyl peroxide were added and stirring was continued until the solution was clear and homogeneous (approximately 1 hour). The solution thus prepared was applied to a PET protective film in different layer thicknesses using a laboratory doctor. The layers obtained were then dried at room temperature for one day and finally at 35 ° C. for 3 hours.
• a polyamide Schmelzlclebers Macromelt 6208 ®, Henkel
• a low-oxygen melt was produced from the components of a nyloflex ® FAH printing plate using the above-mentioned process.
• the two-layer composite D2 / N was then produced by calendering in the depot layer described, a commercially available PET film being used as the second dimensionally stable support.
• the two-layer composite D2 / N from Example 3a was separated after storage for one week, that is to say the depot release layer D2 was removed from the precursor layer.
• the peroxide-containing precursor layer V was heated to 160 ° C. in a normal air atmosphere for a period of 20 minutes.
• the two-layer composite D2 / N from Example 3a was separated after storage for one week, that is to say the depot release layer D2 was removed from the precursor layer.
• the peroxide-containing precursor layer V was first annealed at 80 ° C. for 3 hours and then heated to 160 ° C. in a normal air atmosphere for a period of 20 minutes.
• Another peroxide depot adhesive layer Dl was prepared as follows: 64 g of an ethylene-propylene-diene terpolymers (Buna EP G-KA 8869, Bayer) and 6 g of an aliphatic Esterweichmachers (Plastomoll ® DNA, BASF) were dissolved in 260 ml of toluene at 110 ° C solved. After the solution had cooled to 60 ° C., 30 g of dicumyl peroxide were added and stirring was continued until the solution was clear and homogeneous (approximately 1 hour). The solution thus prepared was applied to a PET protective film in different layer thicknesses using a laboratory doctor. The layers obtained were then dried at room temperature for one day and finally at 35 ° C. for 3 hours.
• a low-oxygen melt was made from components of a EPDM-based cover plate layer described in patent no. EP 326977 (binder: Buna EP G-KA 8869, Bayer) according to the above. Process manufactured.
• the two-layer composite DI / V was then produced by calendering in the depot layers described, a commercially available PET film being used as the second dimensionally stable support. - » -" Y ⁇ yy
• the two-layer composite of peroxide depot adhesive layer and elastomeric pressure element-forming layer thus obtained was stored for one week at room temperature.
• the two-layer composite DI / V from example 4a was heated to 160 ° C. for a period of 20 minutes in a normal air atmosphere after storage for one week.
• the two-layer composite DI / V from Example 4a was first tempered for 3 hours at 80 ° C. after storage for one week and then heated to 160 ° C. in a normal air atmosphere for a period of 20 minutes.
• Another peroxide depot adhesive layer Dl was prepared as follows: 64 g of a cyclic rubber (Vestenamer ® 6213, Creanova) and 6 g of an aliphatic Esterweichmachers (Plastomoll ® DNA, BASF) were dissolved in 150 ml of toluene at 110 ° C. After the solution had cooled to 60 ° C., 30 g of dicumyl peroxide were added and stirring was continued until the solution was clear and homogeneous (approximately 1 hour). The solution thus prepared was applied to a PET protective film in different layer thicknesses using a laboratory doctor. The layers obtained were then dried at room temperature for one day and finally at 35 ° C. for 3 hours.
• a low-oxygen melt was made from components of a flexo-plate recipe as described in patent no. EP 326977 on an EPDM basis (binder: Buna EP G-KA 8869, Bayer) according to the above. Process manufactured.
• Example 5a The two-layer composite DI / N was then produced by calendering in the depot layers described, a commercially available PET film being used as the second dimensionally stable support.
• Example 5a The two-layer composite DI / N was then produced by calendering in the depot layers described, a commercially available PET film being used as the second dimensionally stable support.
• the two-layer composite of peroxide depot adhesive layer and elastomeric pressure element-forming layer thus obtained was stored for one week at room temperature.
• the two-layer composite DI / N from Example 5a was heated to 160 ° C. for a period of 20 minutes in a normal air atmosphere after storage for one week.
• the two-layer composite DI / N from Example 5a was first tempered for 3 hours at 80 ° C. after storage for one week and then heated to 160 ° C. in a normal air atmosphere for a period of 20 minutes.
• a further peroxide depot adhesive layer D1 was produced as follows: 80 g of an ethylene-propylene-diene terpolymer (Buna EP G-KA 8869, Bayer AG) were dissolved in 260 ml of toluene at 110 ° C. After the solution had cooled to 60 ° C., 20 g of dicumyl peroxide were added and stirring was continued until the solution was clear and homogeneous (approximately 1 hour). The solution thus prepared was applied to a PET protective film in different layer thicknesses using a laboratory doctor. The layers obtained were then dried at room temperature for one day and finally at 35 ° C. for 3 hours.
• an ethylene-propylene-diene terpolymer (Buna EP G-KA 8869, Bayer AG) were dissolved in 260 ml of toluene at 110 ° C. After the solution had cooled to 60 ° C., 20 g of dicumyl peroxide were added and stirring was continued until the
• a pigmented elastomeric printing element-forming layer V was prepared as follows: 87 wt .-% of an ethylene-propylene-diene terpolymer (Buna EP G-KA 8869, Bayer AG) and 13 wt .-% of a basic carbon black (Printex ® A, Degussa -Huels) were in one Haake laboratory kneader pre-corned. The precompound was then dissolved in so much toluene that a 25 percent by weight solution in toluene was formed. The solution thus prepared was applied to a PET protective film using a laboratory doctor blade in such a way that a dry layer thickness of approximately 800 ⁇ m was obtained after the solvent had evaporated.
• the two-layer composite DI / N was then produced by laminating on the depot layer described.
• the two-layer composite of peroxide depot adhesive layer and pigmented elastomeric pressure element-forming layer thus obtained was stored for one week at room temperature.
• the two-layer composite DI / N from example 6a was heated to 160 ° C. for a period of 20 minutes in a normal air atmosphere after storage for one week.
• the two-layer composite DI / N from Example 6a was first tempered for 3 hours at 80 ° C. after storage for one week and then heated to 160 ° C. in a normal air atmosphere for a period of 20 minutes.
• Another peroxide depot adhesive layer Dl was prepared as follows: 80 g of Kraton ® D-1161 NU were dissolved in 190 ml of toluene at 110 ° C. After cooling the
• a pigmented elastomeric printing element-forming layer N was prepared as follows: 88.6 wt .-% of components a nyloflex ® FAH printing plate and 11.4 wt .-% of a basic carbon black (Printex ® A, Degussa-Huels) were mixed in a Haake Laboratory kneader pre-compounded. The precompound was then dissolved in so much toluene that a 40 percent by weight solution in toluene was formed. The solution thus prepared was applied to a PET protective film using a laboratory doctor blade in such a way that a dry layer thickness of approximately 800 ⁇ m was obtained after the solvent had evaporated. The two-layer composite DI / N was then produced by laminating on the depot layer described.
• the two-layer composite of peroxide depot adhesive layer and pigmented elastomeric pressure element-forming layer thus obtained was stored for one week at room temperature.
• the two-layer composite DI / N from Example 7a was heated to 160 ° C. for a period of 20 minutes in a normal air atmosphere after storage for one week.
• the two-layer composite DI / V from Example 7a was first tempered for 3 hours at 80 ° C. after storage for one week and then heated to 160 ° C. in a normal air atmosphere for a period of 20 minutes.
• Table 1 below shows the results of Comparative Examples AI and A2 and Examples 1, 2, 3 and 6.
• samples b) and c) were crosslinked by the thermal treatment, which is demonstrated by the low values of the toluene extract content and the greatly increased breakage voltage.
• the only stored samples remained uncrosslinked.
• a reference sample (comparative example AI) which was kneaded without an initiator also remained uncrosslinked.
• An identical sample comparativative example A2, to which, however, the initiator was added during the kneading process, cured immediately within less than 1 minute. The crosslinked polymer was destroyed in the kneader by degradation and was inhomogeneous.
• Table 2 below shows the results of the comparative examples B1 and B2 and examples 4, 5 and 7.
• samples b) and c) were crosslinked by the thermal treatment, which is demonstrated by the low values of the toluene extract fraction and the greatly increased breaking stress.
• the only stored samples remained unground.
• a reference sample (comparative example B1) which was kneaded without an initiator also remained uncrosslinked.
• An identical sample (comparative example B2), to which, however, the initiator was added during the kneading process, immediately crosslinked within less than 1 minute. The crosslinked polymer was destroyed in the kneader by degradation and was inhomogeneous.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Plasma & Fusion (AREA)
• Manufacturing & Machinery (AREA)
• Printing Plates And Materials Therefor (AREA)
• Manufacture Or Reproduction Of Printing Formes (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Thermal Transfer Or Thermal Recording In General (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Laminated Bodies (AREA)

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